Seed iron and zinc content and their response to phosphorus fertilization in 40 Colombian bean varieties

The improvement of beans in Colombia has produced a large number of varieties for different agro-ecological zones and with different adaptation ranges. The objective of this research was to determine the nutritional quality of common bean genotypes from Colombia in terms of iron and zinc content of the seed and to determine how soil fertilization with high or low levels of phosphorus impact yield with these minerals . A total of 40 genotypes were evaluated including released varieties from ICA or Corpoica (of the Diacol or ICA series), traditional landrace varieties from Valle, Nariño and Norte de Santander, and CIAT breeding lines as control. These were planted in Darién in the first semester of 2004 under two-fertilization treatments in complete randomized block experiments with three repetitions. Iron and zinc content was measured in harvested seed using the spectrophotometric method of atomic absorption. Variance analysis showed significant differences for mineral content among genotypes, and between high and low phosphorus fertilization levels with averages of 61.5 and 53.2 ppm for iron and 26.3 and 23.1 for zinc, respectively. Given these results, phosphorus fertilization can increase iron content in bean seeds, but can reduce zinc content in seeds.